The present invention relates to the use of melaleuca oil as a muscle relaxant and analgesic, in combination with other ingredients to produce a penetrating, long-lasting cream for topical application. In particular, the invention relates to the manufacture of a muscle relaxant containing at least five percent, and preferably ten percent, melaleuca oil. The oils of Melaleuca spp. have been used for a number of years as a bactericide and fungicide topically applied to wounds, abrasions, etc. The germicidal nature of melaleuca oil has been known since at least 1930, when it was reported that the oil had a Rideal-Walker co-efficient of 11-13, meaning it has 11-13 times the efficacy of phenol as a germicide. The oil of Melaleuca is distilled from the leaves and terminal branchlets of various Melaleuca species indigenous to the north coast of New South Wales, Australia. Such oil can contain up to fifteen percent 1-8 cineole and a minimum of thirty percent terpinen-4-ol, on a weight/weight basis.
While the existing literature on the uses of melaleuca oil is mostly in anecdotal format, it appears that the oil has never gained wide-spread acceptance as a fungicide even though it has been periodically used for a large number of bactericidal or fungicidal purposes. While the medical use of melaleuca oil reached its peak in the mid-twentieth century, its use since that time has steadily declined. Surprisingly, it would appear that the use of melaleuca oil as a muscle relaxant, when used in an appropriate mixture with other ingredients, has heretofore gone undiscovered.
Melaleuca oil is a complex mixture of approximately forty-eight separate compounds. While it is not known precisely why the oil produces the analgesic and therapeutic affects observed in the present invention and in its germicidal properties, it is believed that the concentration of terpinen-4-ol may be a major factor. At the same time, the low concentration of another major constituent (1,8-cineole) is advantageous due to its known propensity for skin irritation.
Therefore, applicant's discovery of this new use of a mixture containing at least five percent, and preferably ten percent melaleuca oil, is surprising in that it produces the desired affect where many other products fail. While analgesic balms have been known for some time and are currently mass-marketed for the relief of local muscle and joint discomfort, such products are limited effectiveness and have relatively short duration, and require relatively frequent reapplication. There is therefore a need for an effective analgesic and muscle relaxant which is penetrating, long-acting, effective and which produces no adverse skin reaction.